This invention relates to hand-operated dispensing pumps sometimes called trigger sprayers. More specifically, this invention relates to trigger sprayers adapted to selectively emit a spray cone or a foaming discharge.
The prior art is replete with trigger sprayers of various types. An example is disclosed in the McKinney U.S. Pat. No. 4,161,288 wherein the pump comprises a vertically disposed cylinder having a piston stroking as a trigger lever is pulled back and forth. This pumps the liquid from an attached container out a delivery tube to a nozzle.
Typically, trigger sprayers are provided with a nozzle including a rotatable nozzle cap. The delivery tube from the pump usually terminates in a bushing and the cap snaps over the bushing. The delivery tube passes the liquid toward the front end of the cap where it is usually introduced tangentially into a so-called xe2x80x9cswirl chamberxe2x80x9d on the rear face of the front end of the cap. In the chamber the liquid increases in angular velocity as it swirls toward the orifice and finally discharges in the form of a spray cone.
A shut-off valve may be provided between the bushing and nozzle cap wherein channels in the respective parts align in use, but the flow may be cut off by rotating the cap to a xe2x80x9cstopxe2x80x9d position wherein the channels do not align.
In some sprayers the orifice and swirl chamber have been offset from the axis of the cap. In the Hayes U.S. Pat. No. 4,247,048, for instance, the orifice is offset and the discharge may selectively be in the form of a stream or a spray, depending on the depth of the channel on the delivery tube where it communicates with the swirl chamber.
The concept of a foaming sleeve surrounding the spray cone emitting from a trigger pump orifice is disclosed in the Shay U.S. Pat. No. 4,669,665. Here the cone engages the inside of the foaming sleeve, mixes with air, and discharges as a foam.
The further Shay U.S. Pat. No. 4,768,717 issued Sep. 6, 1988 teaches the idea of introducing air inwardly about the outside of a foaming sleeve to the rear end of the sleeve to enhance the foaming.
A number of prior patents have suggested means in a trigger sprayer for selecting either a foam or a spray type discharge. An example is disclosed in the Shay U.S. Pat. No. 4,767,060 wherein a foaming collar is reciprocably mounted on an annular support extending forward from the nozzle. The sleeve can be moved into either a forward position wherein it is engaged by the emitting spray cone produces foam, and a rearward position adjacent the orifice wherein the collar is not contacted by the spray, and the discharge is in the form of a spray.
A further disclosure of a selectable spray or foam discharge is found in the Corsette U.S. Pat. No. 4,779,803 wherein a centrally apertured plate has a plurality of rearward legs which telescope into the nozzle cap about the orifice. The plate is movable as the legs slide into the cap or out from it. The plate can be set in a position where the aperture is adjacent the orifice and does not interfere with the spray or is away from the orifice, forward of it, and is impacted by the spray to produce a foam.
More recently foam/spray discharge selectability is disclosed in the Tasaki et al U.S. Pat. No. 5,344,078 and the Foster et al U.S. Pat. No. 5,767,385. In these patents a foaming sleeve or bore is pivotally attached to the side of the nozzle cap on an axis generally perpendicular to the orifice axis so that it can be swung down from an idle position to close to the orifice so that the spray from the orifice contacts the sleeve and a foam discharge is produced.
The structure of some earlier selectable discharge pumps interfere with the symmetry of the pump nozzle. The selectable feature of earlier uses often requires an awkward lateral or forward projection which can readily break off or catch on things. Further, some of these earlier structures are not easy to use.
The present invention has for an object to provide a selector symmetrical about the nozzle axis, compact and easy to use. Briefly, the invention comprising a hand-activated pump having a nozzle cap rotatably disposed at the front end of the pump. The cap has a front end wall formed with a spray orifice offset from the axis. In the invention a sprayer/foamer selector wheel is rotatably amounted on the axis and adjacent the front end wall of the cap, the wheel incorporating a foam sleeve and a sprayer window offset from the axis. By manually rotating the wheel, the user can register the window or sleeve with the spray orifice to produce spray or foam.
In a modification the wheel may be provided with a plurality of alternating sleeves and windows, all offset from the axis. The attachment of the selector wheel to the nozzle cap may be by a snap-fastener-type connection disposed on the axis and serving as a spindle. The head may be integral with the cap, and the socket in the center of the wheel.